On Tue, 11 Aug 2020 at 11:26, <geoff@hughes.net> wrote:
Reboot stopped at emergency mode.

journalctl -xb does not list any complaints (that I can find), but
there's clearly something wrong! Any suggestions as to diagnosis?

kernel is 5.7.9.200. selinux is disabled.

livecd boot is OK; disk is accessible. 

I saved the output of journlctl, so its available for interrogation. No obvious complaints

Thoughts? Diagnosis?

Are you using UEFI Secure Boot? 
Was grub2 updated recently?
Is this a multi-boot system?

Other distros, including RHEL, have reported boot failures after applying updates to grub2 for CVE-2020-10713.  

--
George N. White III